An Unexpected Guest
by Kurisaki-sempai
Summary: *Stars Through Darkness spin-off* After Black Rock Shooter finds a strange old diary in a vast library, she later finds herself in the company of a certain magician from another world. How will this little meeting turn out?


**Author's Notes: Heya, all~ :3**

**I just had to write this little one-shot since the idea's been buzzing around in my head for some time now like an annoying itch. I made this one based on a remark Rock made in chapter 3 of my currently ongoing fanfiction, **_**Stars Through Darkness**_**, and it's set either before the actual plot, or a few years after the current chapter (probably the latter… nope, cross that—it really is set a few years **_**after**_** the current chapter). It's kinda just a bit of a cross-over I was planning on making to the main story, though I'm still not sure if I really should go on with the idea…**

**Anyway, read and review, please~! X3**

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><p>Black Rock Shooter had not always been one for books. She was a pugilist, a warrior, a hermit of sorts; she was one who traveled around almost aimlessly like the wind, often finding herself in deep shit, but nothing too tough for someone like her to handle. But if you've been living for what seems like forever with surviving and staying alive as an everyday routine like she has, you tend to look for things to occupy your time every once in a while.<p>

Here she was, finding herself in a vast chasm-like hall of books as far as she could see. The bookshelves were tall enough to almost reach the high ceiling, with what appeared to be couches suspended by ropes and chains hanging from the ceiling placed by the wall-like shelves. Strange as they looked, they seemed stable enough to hold anyone comfortably. The peculiar furniture hung along with glowing spheres that served as a source of illumination. The carpeted floor, along with the aforementioned couches, were themed a bright red color.

Black Rock Shooter had somehow just ended up in this immense library after she was exploring an old sanctuary of derelict architecture as if she just stepped into a portal—there was no sign of the dusty, debris-filled ruins she had just investigated, and it made no sense if this place was part of that place—the carpet and shelves were clean and spotless, obviously well-kept, nothing like the other book-filled places she had gone to, which were just as messy as any place in the Otherworld, or what remained of the once-pristine Earth.

She walked through the shelves with something akin to wonder and curiosity, checking the books which caught her eye for some time in relative peace. Despite it being so quiet, the library didn't carry an air of danger at all.

She had just placed another book back into its place when another one got her attention: a faded, tattered book which was so old, it looked like it would immediately combust if one were to place it near a little ember. It was so worn that the book looked too out of place among the clean shelves. Rather conveniently, the book was just placed on a couch which rested on the ground, which told her someone had probably just left the little thing.

Walking over to the couch, she picked up the book and sat down. She opened it and got a little surprised at its contents: It was written in an indescribable text unlike any of the books she had found here. But what confused her was that she could actually read and understand it as well as the language she was accustomed to.

"…_I don't understand. Why would they agree on such a stupid thing? They have been our allies, our friends, our brothers-in-arms!"_

That statement had already gotten Black Rock Shooter interested. Already engrossed in the tattered thing in her hands, she continued to read.

"_They have decided to extinguish our very kind from the face of existence… Why, just why? How can they call themselves holy beings if they would ever plan a mass genocide? The angels can't just do this… Why, just because we are inferior to them? Just because we are more capable of sin than they are, they would just treat us like animals?_

_I'm tired, and I believe I should rest any time now. With this, I pray that the heavenly forces would take time to reconsider their decision."_

This book was a diary, then? It was definitely intriguing. Who could have written it? Interested and disturbed by the written record, she turned the page to read the next entry.

"_They came. They really came. To our utmost horrors, the angels had actually concluded that our race be destroyed. I saw them raze our village, killing everyone in their path, sparing no one… I remember how they had mercilessly slaughtered us like pigs. I hated it. _

_I'm currently in hiding as I write this, along with some refugees that were able to escape. I obtained word that they have already attacked all major settlements, and our own brethren have engaged the angels in combat, and even the Four Horsemen have joined the fray. I sincerely hope that the balance of this war would tip in our favor, or it would be too late for us all."_

Now, this was totally horrifying. Some massacre had happened ages ago? Of what? Of what race was this writer talking about? And seriously, _angels _were the bad guys here? Black Rock Shooter had never seen or met one before, neither did she know if they really do exist; but weren't they supposed to be the good guys? Even more anxious about what the next entries would say, she turned the page. Disturbingly, this next one had dark splotches on it. But on closer inspection it turned out the stains were a dark brown color—dried blood.

"_This is likely the last message I would get to write. I had joined what remained of our forces recently, and we were planning on an ambush on a squadron of angels travelling northward. We had noticed that there were prisoners with them—severely injured men, women, and children, in no shape to escape, let alone fight, probably ones from different villages they had annihilated. What made me sure of this was that one of them was a little white-haired boy I recognized from my village—I had seen how an angel slaughtered his parents as they fought to protect their child, and I had just watched in fear… if this rescue would make up for my cowardice, so be it._

_The plan had ended in utter failure, with disastrous results. One of the prisoners had noticed us, and mouthed with his lips, 'get away.' I had mouthed back 'it's okay,' in reply, not immediately understanding why he warned us, we went on with the plan, only then realizing our stupidity. The whole thing was a trap to lure us out. As we engaged the angels who held the prisoners captive, even more suddenly appeared to pick us off, outnumbering us ten to one. I had seen that boy try to fight too, but ended up in a brutal reenactment of what I had seen, the ones who tried to protect the prisoners ending up butchered. Too many of us were killed, and others were able to escape, but barely clinging on to life. The angels just sent scouts after the escapees, though I was able to kill the one who went after me before he could do so himself._

_As I think about the events that had happened these past few days, I wondered, would this be the end for us? Would we really just be wiped out in a humiliating massacre of our once-glorious race, instead of dying in battle like the warriors we are? Dear God, why let your children slaughter each other like this? What had we done that we would deserve extinction?_

_I'm at my limit. I don't think I would be able to write any longer. Please, to any individual who would find this record, I ask of you: remember us. Remember the Nephelim, the Creator's firstborn."_

The text ended there. Black Rock Shooter turned to the next few pages, only to find them empty. Several things went to and fro in her head after reading the thing, but her train of thought came to a sudden halt when she heard a girl squeal from nearby, accompanied with the sound of dropped books. With her inhuman reflexes and lightning speed, Black Rock Shooter's hand went straight to her katana's hilt, unsheathing the Black Blade in an instant, pointing it directly at the newcomer.

"Who are you? W-What are you doing here?" The girl uneasily asked. She had long, flowing red hair that reached down to her thighs, and wore a white long-sleeved shirt with a red necktie, along with a black vest and a knee-length skirt. Two pairs of small, bat-like wings protruded from her back and the sides of her head, and she had a forked tail that fidgeted nervously. Strange people like these were the norm for Black Rock Shooter that finding one who did not have any weird appendages would be considered peculiar.

"_Every damn time,"_ Black Rock Shooter thought, referring to all those other times she had found time to read. "I was just reading. You're not going to chase me away, are you?" she calmly asked.

"Not unless you're planning on stealing our books too," the red-haired girl replied. She took a defensive stance when all of a sudden she turned towards a sound from behind her.

Suddenly, a small sphere of glowing blue energy zoomed towards Black Rock Shooter, but she stood her ground and deflected the shot upwards with her katana, making a small hole in the ceiling.

"I didn't ask you to disturb my reading with your bickering, Koakuma." came another voice. A short, pale-skinned woman revealed herself, hovering a few inches off the ground. She was clad in a frilly, thick lilac dress that seemed to be more suited for sleeping, and the ends of her ankle-length purple hair were adorned with blue and red ribbons. Her dress included a hood decorated with a gold crescent on one side, and she carried an open brown tome that casually levitated from her palm.

The woman turned her attention from the red-haired succubus, presumably named Koakuma, toward Black Rock Shooter. "Let's try to be more civil, shall we? Put away your blade; we can just discuss this matter normally." She relaxed and set her feet on the carpeted floor. "What is your name?" she asked, "I didn't see you come in through the door, and neither did I sense anyone breaking in through the windows."

Sensing no hostile intent from the woman, Black Rock Shooter sheathed the Black Blade into place. "You don't always shoot your visitors, do you?"

"I apologize for that," The woman answered, "Now, your name, please?"

"Right," she replied, "My name is Black Rock Shooter. I just… happened to end up here, though I don't know just how it happened."

The woman slightly bowed, "Nice to meet you, Black Rock Shooter. I am Patchouli Knowledge, the librarian of Voile, this library." She gestured towards the red-haired succubus, who already felt left out from the conversation. "And this is Koakuma, my assistant. I apologize for her earlier behavior. We just happen to have a certain black-clad individual who comes here to steal my books every so often."

"Must be hard keeping track of which books are stolen, judging from how numerous they are," Rock said.

"You have no idea." Patchouli groaned. She noticed the book Rock had been reading on the couch, and a brief look of surprise was on her face before she composed herself. She pointed a pale finger at the tattered book and asked, "Were you reading that before Koakuma noticed you, I wonder?"

"I was," Rock replied.

"You don't happen to understand what it says, do you?"

Rock's curiosity perked up. "I do, actually." She walked up to the couch and picked up the book carefully, "From the information it contains, I have reason to believe that it was a memoir or diary; the final entry suggests that its writer was at death's door as he or she wrote it."

Patchouli's calm demeanor instantly shifted to one of childlike delight. "Oh, splendid! And such intriguing information, too!" she exclaimed, "I have always wanted to know what information that old book contains; I have never discovered information regarding the used alphabet, neither have I found anyone capable of reading it, until now."

She turned to leave, and then beckoned for Rock to follow her. "Come, Black Rock Shooter. I believe it would be best if we were to be acquainted." She turned towards her assistant, "Koakuma, have Sakuya prepare snacks and refreshments for me and our guest. I think we are going to have a lot to talk about."

"But Patchouli-sama," the succubus asked nervously, "What about the Mistress? Isn't she supposed to know about-"

"Have Sakuya inform her, then," said Patchouli before flying off, leaving Koakuma and Rock to themselves.

Rock looked a little bemused. "Your master seems… strange," she said.

"She's like this when it comes to learning stuff," Koakuma replied, "You could say that she totally craves what her name stands for."

The both of them started heading up the path Patchouli flew off to, though Koakuma just unceremoniously hovered above the ground, with her wings steadily flapping. "So, who's Sakuya?" Rock asked.

"She's the head maid of the mansion," Koakuma replied.

"You two are not the only ones around, then… wait, a mansion?" Rock asked incredulously, "This library seems big enough already."

"Oh, it's quite big alright," Koakuma said, "And Voile is just a fraction of the mansion's size."

"Black Rock Shooter?" Patchouli's eager voice called from up ahead.

"Anyway, I have to go comply with Patchouli-sama's request. Do entertain her, Black Rock Shooter," Koakuma flew higher and went out of sight.

A few minutes later, Rock found herself in what appeared to be the center of the whole library; the edges of the bookshelves made a square perimeter around the area, and a few red-cushioned armchairs were set beside two tables stacked with books. Patchouli was taking off the books from the first table, moving them to the other one. It looked like she was only moving them a few at a time, and she was panting and coughing while doing so as if it were too rough a job for her. Upon noticing Rock, she gestured for the black-clad girl to come over and asked, "Could you give me a hand?"

Rock nodded and headed towards her, moving the books at a faster rate than the librarian. "You don't seem used to this," she said.

"I suffer from poor health, Black Rock Shooter, and I'm not one for physical labor," Patchouli said with a cough, "And it's usually Koakuma or the gate guard who helps with putting these away. I'm just a tad bit eager to know about what knowledge that book holds."

"I see," Rock replied, "And you can just call me Rock if you'd like. I think my title is a bit of a mouthful."

"Alright then."

The two of them finished a few minutes later, with Patchouli setting herself on one of the chairs as soon as they were done. She beckoned for Rock to sit down as well, to which the other girl acceded with. In a moment, a maid suddenly appeared out of nowhere, carrying a tray with sandwiches, slices of fruit, and a kettle of tea; her sudden entrance surprised Rock, and her hand barely tugged on the Black Blade's hilt before Patchouli waved her down. Settling herself, Rock guessed that this was the Sakuya that Koakuma talked about earlier; she was a tall, beautiful woman, dressed in a cobalt-blue maid's outfit, and her short, silky silver hair looked lovely with her ice-blue eyes.

The maid set the tray on the empty table and poured tea into two cups. She gave Rock an emotionless glance before disappearing a second later.

"Whoa," Rock said, "how did she get to prepare these so fast? And how did she pop out of nowhere?"

"The ability to control time. It's rather convenient, don't you think?" Patchouli said, picking up a cup and sipping on her tea evenly. "So, how about we introduce ourselves a little further? I'm a little interested in what you have to say; you're quite… different from others I've seen." She set her cup down. "And I believe you would like to know a few things, as well."

"Didn't you say that you wanted to know about this thing?" Rock asked, holding up the shabby book she had been holding.

"I do, but would it not be a little impolite?" Patchouli chuckled before popping a piece of fruit into her mouth. "Aren't you going to eat?" she asked.

"I don't eat," Rock replied, "or at least, I don't need to. Eating is… something like a source of mirth for me, or if it's absolutely necessary."

"How odd," Patchouli said pensively, then lightly nudging Rock's dish of food toward her, "Why don't you try some, then? Sakuya's cooking is quite delightful, I tell you."

Rock just stared at the food uncertainly for a few seconds before timidly taking a sandwich off the plate. Patchouli couldn't help but giggle at seeing the light blush that appeared on the girl's cheeks as she ate—it looked rather adorable. "It's good," Rock softly said.

"Isn't it?" Patchouli said, smiling. She watched Rock indulge herself in relative silence for a while, now fairly interested in the girl. A few moments of silent contemplation later, Patchouli asked, "Say, Rock… what are you?"

Rock gave her a puzzled look. "What do you mean?"

"You're not exactly human, right? From what I've seen, your reflexes are too immediate to be called human, and you just mentioned that you don't need food," the librarian stated, "so, what are you?"

Rock was silent before speaking, "To tell the truth… I don't know just what I am, or who I am, either."

Patchouli raised an eyebrow. "Really? Don't you remember anything?"

"Just my name… and a memory."

"What was it like?" Patchouli asked.

"It's a little strange… I remember a girl holding on to my hand, screaming incoherently. Then I felt a sensation as if I were falling, and that girl screaming a name I don't know of. Everything before or after that is a blur." Rock brought a hand to her temple, seemingly disturbed by the memory. "What's strange is that I feel like I should know that name…" She was silent for a few seconds before speaking up again, "What about you? Can you tell me something about yourself?"

"Of course," Patchouli answered, "I used to be quite an infamous witch way back in Europe before knowing this mansion's mistress."

"Are you talking about the Middle Ages?" Rock asked, recalling information she had once read.

"Indeed I am," Patchouli replied, "I'm far older than I look, you know. That was an utterly troublesome time for the likes of myself—It couldn't be helped that the common people were terrified of us. Humans tend to fear what they don't know, don't they?"

Rock simply agreed before bringing up another subject. "I was wondering… where am I? And do you know how I ended up here?" she asked.

"I was wondering when you would ask that particular question," Patchouli replied, "This is the Scarlet Devil Mansion, in the land of Gensokyo. This place has been isolated from the rest of the world for centuries, and the 'normal' things you would find here have been known to be mythical or extinct in the outside world for ages. As for how you ended up here… well, the only possibility I can think of is that you somehow stepped into a gap or portal."

"Isolated? Outside world? Portal?" Rock asked, confused.

"You could say that Gensokyo exists in a dimension of its own," Patchouli explained, "And the one responsible for Gensokyo's seclusion? As for her, no one here knows just where she could be; she disappeared a few years ago, and ever since, the barrier separating the land from the outside seems to have weakened, and we get outsiders ending up here more often than before. Our recent 'visitors' have been… unfriendly, to say the least."

"Any idea on how I can leave?" Rock asked.

"Maybe you could find a portal? If I assume correctly, they pop around the land from time to time. Just be careful , though; you never know where you'd end up in."

The two of them conversed undisturbed, talking about certain subjects here and there; it was only then that the purple-haired librarian remembered what the two of them were supposed to be doing. "Oh, I almost forgot," said Patchouli, "Let's get started with that diary, Rock." She took a book that she set aside earlier and opened it—the pages were empty. "Just read what it says aloud, and I'll handle the writing."

Rock nodded and opened the tattered diary, carefully handling the thing so as not to accidentally tear a page off the old book, and the two began. Instead of using a pen, Patchouli simply cast some sort of spell, making the words from Rock appear on the once-untouched pages one by one. The task had taken about half an hour, and after it was done, the librarian silently mulled over the new knowledge she had received.

"The Nephelim, eh…?" Patchouli muttered.

"Any idea on what they are?"Rock asked.

The librarian thought about the question for a moment before answering, "Well, from what I know, the Jewish Bible claims that they are supposed to be the offspring of lustful angels who have descended to earth to engage in… _questionable_ affairs."

"But the writer claims that it was the angels themselves who extinguished their kind," Rock mused, "why destroy a race directly related to them? And who are the 'Four Horsemen' that it mentioned? Got any idea who they are?"

"The Four Horsemen are also mentioned in the Jewish Bible," Patchouli answered, "That's rather intriguing… they are said to arrive when the Apocalypse comes, so why are they mentioned in a record that's probably ages old?"

"'The Creator's Firstborn…'" Rock muttered, "doesn't this suggest that this particular race may have existed ages before known history?"

"Who knows?" Patchouli uttered before giving an exasperated sigh, leaning on her chair.

"What's wrong?" Rock asked.

"It's just…" Patchouli said sheepishly, "Just when I thought my questions would be answered, even more pop out of nowhere. But, I must admit…" She turned her attention to Rock, "I haven't been this hungry for knowledge in a long time. I have you to thank for that, Rock."

"It was nothing," Rock replied, "I guess I should also thank you for being the first person I got to normally talk with in ages." She gave a light chuckle before dishearteningly saying, "But, what now? This is all the information we have, and I might not be staying here for long."

As if on cue, the both of them heard the faint sound of wind coming from nearby. They both stood from their seats, confused, before walking up to one of the library's hallways—there was what looked like a ring floating in midair, encircled with glowing blue. The sound was coming from it. Rock cautiously approached it, and the sound grew stronger, one that she could now recognize—this was a portal that led back to the Otherworld.

"I believe that's your one-way ticket back, Rock." Patchouli said, with a small hint of disappointment in her tone. "I hope you could have stayed longer."

"I guess I'll be leaving now," Rock faced her, "Thank you for your hospitality, Patchouli."

"Thank you, too," The librarian said. Rock had only taken a few steps toward the portal when Patchouli asked, "Rock, I'm curious…" she began, "What was the name of the person that the girl in your memories mentioned?"

Rock stopped, and went silent for a while. "Mato," she said, then stepping into the portal that would take her back. "the name was Mato."

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><p><strong>Black Rock Shooter ~ Huke<strong>

**Touhou ~ ZUN / Team Shanghai Alice**

**Darksiders ~ Vigil Games and Joe Madureira**

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><p><strong>AN: Well, how was it? xDD;<strong>

**Most of the things mentioned here take reference from events that happen later in **_**Stars Through Darkness, **_**since I already planned a vague outline before working on the first arc*le evil laff*.**

**I probably will make more of these random crossovers with BRS, testing on which anime/game/manga/franchise would go well with characters or events from BRS to go with **_**Stars Through Darkness**_**. :3**

**Please Review~! (^‿‿^)/**

**P.S. Might be doing Blue Exorcist next~**


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